This poster was created in 1846 of signals at the Portland Observatory.
At the time this poster was made how long had the Observatory been signalizing? Hint: The Observatory began signalizing in 1807.
The poster is seperated into two sections, the top is for general signals and the bottom is for private signals.
Compare the flags shown here with the ones you looked at earlier.
Are any of the flags the same?
Which of the general flags have remained the same?
Which of the private signals have remained the same?